Combined oil and gas burner



Nov. 1, 1932.

M. A. POWERS OOIBINED OIL AND GAS BURNER Filed D90. 15, 1930 INVENTORATTORNEYS Patented Nov. 1, 1932 UNITED STATES PATENT OFFICE MILTON A.POWERS, OF DETROIT, MICHIGAN, ASSIGNOR TO THE TIMKEN SILENT AUTOMATICCOMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN COMBINED OILAND GAS BURNER Application filed December 15, 1930. Serial No. 502,598.

The invention relates to fluid fuel burners of the intermittentlyoperating type. Ineluded within this general type are burners designedto operate with gaseous fuel and also burners designed to operate withliquid fuels, each of which has its own peculiar advantages. Thus thegaseous fuel is taken from a supply main and dispenses with thenecessity of refilling tanks incident to the use of liquid fuel.

In On the other hand the cost of operating with liquid fuel is generallyless than that with gaseous fuel and in very cold weather is generallymore satisfactory, particularly in view of the fact that the gaspressure of supply mains is lowest in severe weather. To combine theadvantages of both types of burner I have devised a construction whichis adapted to use liquid or gaseous fuels alternatively and whichrequires no further adjustment than the mere throwing of a switch tochange from one to the other. This enables the user to operate underliquid fuel during the season when the greatest amount of heat isrequired and to change to gaseous fuel during milder 1-: weather.

One difiiculty to be overcome in the construction of such acombinedvunit is to secure efficiency in operation with both'types offuel. It is quite common with oil burners to employ a rotary nozzle ordistributor which sprays the oil over a hearth. Such constructions arealso provided with a'fan or other means for propelling an air currentsupplying the news saryair to support combustion andalso facilitatingcommingling of the air with the fuel spray. On the other hand, gasburners are or a different type of construction and one which can not bereadily combined withan oil burner without interference. My improvementovercomes these difliculties by so arranging the elements of the'gasburner as to in no way, interfere with the efiicient operation of theoil burner and at the same time to' cooperate with elements of the oilburner to produce the highest efiiciency when gaseous fuel alone isused. The invention therefore consists in the construction ashereinafter set forth.

In the drawing:

Figure 1 is a diagrammatic view showing the arrangement of the combinedgas and oil burner and the control device therefor;

Figure 2 is a cross section through a portion of a furnace in which mycombined burner is installed.

As shown in Figure 2, A is the wall of the combustion chamber within afurnace of any type, B is a hearth suitably located within the chamberA, and C is a rotary oil nozzle or distributor arranged centrally of thehearth and operated by a suitable electric motor (not shown). The hearthB is provided near its periphery with a refractory ring D having agroove E therein into which is directed the spray of oil and currentof'air from the rotary member C. This is adapted to produce an 05effective vaporization of the oil and commingling of the same with theair so as to produce a radiant flame. The intermittent operation of theburner is controlled by the usual electrical devices including athermostat F which controls the starting and stopping of the motor andthe simultaneous opening and closing of an oil valve G. Thus wheneverheat is required the operation of the thermostat will start the motorand open the 75' valve G to supply air and oil.

The gas burner which is to be alternativel used comprises an annularconduit H whic is imbedded in the hearth adjacent to the refractory ringD and which at suitable in- .tervals is provided with upwardly extendingnipples I which project a short distance above the hearth and oppositethe groove E in the refractory ring D, but not so as to interfere withthe free travel of the oil spray from the burner to said refractoryring. Each nipple has a cap J with a discharge orifice K directedtowards the groove E so that whenever gas is discharged it will bedistributed around the hearth in said groove.

The air for supporting combustion is supplied by the same fan whichsupplies the air when liquid fuel is used and the quantity of gasdischarged from the nipples is so proportioned as to be proper foroperation with the quantity of air. In actual practice the method ofadjustment to accomplish proper proportioning of oil and gas foreffective combusition in a given installation is as follows:

By a survey of the heating system the required rate of oil consumptionfor satisfactory operation is determined. The oil feed to the burner isset at this rate, the air supply is then varied until the proper qualityof flame for eflicient combustion is obtained at which time the airshutter is locked. Transfer is then made to gas in place of the oil andthe gas rate adjusted until the best combustion is obtained at thepreviously fixed air rate. The same adjustment may, however, be effectedby first setting the gas rate, adjusting the air relative to the samefor proper combustion and then setting the oil for proper combustionwith the air. This method has the double advantage first of obtaining anefficient heating flame with either gas or oil and second, that thenumber of heat units liberated at a given time with gas or oil issufficiently close to produce the desired heat with either fuel. Thedifference in rate of heat release is.automatically compensated for bythe somewhat longer period of operation with the fuel having a reducedheating value.

The control of the gas supplied to the conduit H is through the mediumof an electrically operated valve L which is opened simultaneously withthe starting of the motor and is closed when the current of the motor iscut off. As the liquid and gaseous fuel are never used at the same time,I control their alternative use by a single switch M which when thrownin one direction will throw the electrically operated fuel valve G intocircuit and when thrown in the opposite direction will cut out thisvalve and throw into circuit the electrically operated gas valve L. Thusin either position of the switch M the starting of the motor through theoperation of the thermostat F will open the particular valve G or Lwhich is in circuit while the cutting out of the motor will also cut outthe circuit of this valve.

To provide for the proper proportion of quantity of gas to air, aregulated valve N is provided in the gas supply line 0 and a gaspressure regulator P may also be included in the line 0 to maintainsubstantially con .stant pressure at the burner. A suitable gas pilot Qis provided for ignition of either of the fuels and this may becontrolled by a solenoid valve R or other suit-able means for increasingthe fiame'when the motor is started. However, these auxiliary devicesand the other electrical controls or regulators which usually form apart of the system may be of any suitable design and will not bedescribed in detail.

In use, whenever it is desired to change from one fuel to another, thisis accomplished by throwing the switch M and without the necessity ofany adjustments of either the oil or the gas burner.

What I claim as my invention is:

1. A fluid fuel burner comprising a motor driven rotary member forspraying liquid and for supplying air to support combustion, arefractory ring against which said fuel and air is directed and meansfor alternatively supplying a proportionate quantity of gaseous fuel tosaid refractory ring and for cutting off the liquid fuel supply.

2. A fluid fuel burner comprising a hearth having an annular refractoryring at the peripheral portion thereof, a motor driven rotary member atthe center of said hearth for spraying liquid fuel and supplying aproportionate quantity of air to support combustion, said air and fuelbeing directed against said refractory ring, agas supply conduitimbedded in said hearth and having a series of discharge jets directedagainst said ring, and means controlling the liquid fuel and gas foralternatively supplying the same to said burner.

3. A fluid fuel burner comprising a hearth, a refractory ring above theperipheral portion of said hearth and provided with a groove or channelon its inner side, a motor driven rotary member at the center of saidhearth for spraying liquid fuel towards the groove in said ring and forsupplying a proportionate quantity of air to support combustion, a gasconduit imbedded in said hearth provided with a series of discharge jetsextending above said hearth and directed into said groove, and meanscontrolling the gas and liquid fuel for alternatively supplying the sameonly when said motor is in operation.

In testimony whereof I affix my signature.

MILTON A. POWERS.

